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wsieffert

Question about Magnetic variation

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Hi,I know there a difference between True Heading and Magnetic Heading, and that this depends on the place on the globe.But is there a way to calculate the Magnetic variation, given the location ?Or should this be looked up in tables, and if so, where ?Thanks, Rob

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No, there's no way to "calculate" magnetic variation and "tables" would be impractical because the lines are not straight. That's why the only place you find the data is on maps intended for navigation.Calhover long and prosper

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FS2002 has incorporated the MAGVAR in a scenery file, magdec.bgl, to plot the MagVar across the globe. A file in the Avsim library, magmsa.zip, explains the contents of this file.

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I've always understood it to be the angular difference between true north and magnetic north. If so, that would make it a simple geometry problem (of course mag north moves though).

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Eeee - if only it WERE that simple..Yep, Magnetic North does indeed move but there's more.. If you look at a plot of the Isogonals (lines of equal magnetic variation) you'll find that they don't conform to any sensible geometric pattern at all. In fact they wander all over the place!MS have no doubt used Isogonal data for FS and I suspect the data in FS2002 is the same as in FS98 - it certainly is some way out from current values.boneshttp://fsaviation.net

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You win the magnetic booby prize, bones!! Correct on your assumptions! Just wonder if FS-ACOF will use updated magvar data.

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Hi guys,Thanks for the input.But my problem is solved, since I needed the mag variation at the location you are flying .And MS helped me by supplying an A: variable MAGVAR that gives me exactly that info.PS.After my 'grounhandling' gauges, I'm working on a Descent Rate Calculator gauge, which tends to explode to a FMC :-)Cheers, Rob

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Aw heck guys...I've always wanted to win a magnetic booby.. :)I hope the MAGVAR is updated. At the moment the choice is building runways that are physically correct but requiring FS98 period charts to fly - or building magnetically correct runways for current charts that don't lie in the right place on the ground..boneshttp://fsaviation.net

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